The invention relates to an adjustable hinge device of a motor vehicle seat. The hinge provides for an adjustment of a first joint part relative to a second joint part about a hinge axle.
A variety of embodiments of such hinge devices are well known In the art, reference is mode by way of example only to the prior printed publications of the German documents as cited in the following: 198 12 895.9, P 44 00 910.0, P 36 16 290.609 and P 36 16 164.0-09.
The adjustable hinge or armature of the type mentioned above is essentially intended to be used for a seat back joint in a seat of an automotive vehicle. It may however also be arranged at other places of an adjustable vehicle seat, e.g., in the underframe of the seat where it adjusts the sluing, i.e. swivelling position, of a sluing support serving as height adjustment of the seat area.
The armatures according to the prior art cited have a disadvantage that particularly comes to bear in their use as adjustable armatures for adjusting the incline of a seat back of a vehicle seat. It is practically impossible to carry the two joint pans relative to each other around the sluing axle without clearance, and so a slight bearing play is unavoidable. In case of a long lever arm, as it is the case with the seat back, even a slight bearing play is clearly noticeable at the upper and thus free end of the seat back. Although it has been tried to reduce the effect of the clearance by elastically pretensioning the seat back in one sluing direction or by providing the armature with elastic means, a clearance in the bearing arrangement of the two joint parts cannot be suppressed in the long run.
The object of the invention is to make a new attempt for an adjustable hinge device. The invention aims at dispensing with carrying a hinge shaft in bearings in a centric manner and at suggesting a hinge that self-centers without any Play.
The solution of the invention is to provide an adjustable armature for a sluing adjustment of a first joint part relative to a second joint part about a sluing axle, for an adjustment device of a vehicle seat. The armature may include the following gear parts; a left planet wheel which is carried in bearings on the first joint part in such a manner that it is rotatable about an axle of the left planet wheel; a right planet wheel that is arranged on the first joint part in such a manner that it rotates about an axle of the right planet wheel; a left toothed quadrant which meshes with the left planet wheel in a left area which is turned away from the right planet wheel; and a right toothed quadrant which meshes with The right planet wheel In an area which is turned away from the left planet wheel whereas the two toothed quadrants substantially run in a centric manner relative to the sluing axle and are connected to the second joint part. The armature may be additionally provided with elastic means which are allocated to at least one of the gear parts and which elastically pretension the meshing in the left area between the left toothed quadrant and the mating left planet wheel as well as the meshing in the right area between the right toothed quadrant and the mating right planet wheal in such a manner that the engagement in the left area and in the right area is free from play irrespective of the angular position chosen between the two joint parts. A driving means may be provided which has a driving connection with at least one of the planet wheels and which effects a relative motion in the left area and a relative motion in the right area between the corresponding gear parts during a drive.
This armature does without a bearing arrangement for a propeller shaft. The second joint part centers itself relative to the first joint part on the two planet gears which are connected to the first joint part. Thanks to the elastic means, the meshing is free from play at any place of the complete area of the sluing angle of the adjustable armature, both in the left area between the left planet gear and the left toothed quadrant and In the right area between the right planet gear and the right toothed quadrant. The second joint part is positioned relative to the first joint part by the corresponding meshing in the two areas. The second joint part does not need a shaft that is arranged in a centric manner relative to the sluing axle. The second joint part is carried off-center by the two planet wheels it is clearly stated that it is not necessary to carry the second joint part in the center, in the area of the sluing axle. Additional planet wheels may be provided to improve bearing and/or to better deflect forces.
The elastic means may be realized in such a manner that the planet gears are pretensioned outward toward the corresponding toothed quadrants and/or that the toothed quadrants are elastically pretensioned inward. The elastic inward pretension of the toothed quadrant toward the planet gears is preferred. The involute gear proved to be particularly efficient for meshing in the areas mentioned. It advantageously contributes to a play-free meshing.
The elastic pretension is preferably chosen to be so high that it is not canceled out under a normal load. A normal load is a load below the load encountered in the event of an accident. A load occasioned by an accident is encountered for example In the event of a rear collision at of a frontal collision and causes safety devices such as belt tighteners or air bags to be triggered.
In an advantageous embodiment, the drive means is a pinion which is arranged on one of the joint parts in such a manner that it is rotatable about the sluing axle and which may be driven. It preferably meshes with the two planet gears. On principle, the drive pinion may also be rotatable about an axle that does not coincide with the sluing axle.
In another preferred embodiment, the drive means is a double-lead screw which is carried in bearings on the first joint part in such a manner that it is rotatable about a worm axle running across the sluing axle and which meshes together with at least one planet gear, preferably with both planet gears. The screw is preferably a double-lead screw consisting of a part with left-handed thread and of a part with right-handed thread. The screw is preferably located between the two planet gears.
In a preferred embodiment, more than two planet gears may be provided. In this embodiment, the additional planet gears are preferably not driven but serve to support and guide the second joint part, The additional planet gear which meshes with the right toothed quadrant may be allocated in this way to the right planet gear. This additional right planet gear is preferably elastically pretensioned relative to the right toothed quadrant. Accordingly, an additional left planet gear may also be allocated to the left planet gear with all the additional features mentioned above.
In a preferred embodiment, the two toothed quadrants are arranged in mirror symmetry relative to an axis of the second joint part which runs through the sluing axle.
It proved advantageous to have the two toothed quadrants forming a unit with the second joint part. Manufacturing is thus simplified.
In an additional improvement, it is suggested to provide outside of each toothed quadrant a supporting arch which is arranged on the outer side of the second joint part that runs evenly spaced relative to the neighboring toothed quadrant and to also provide on the outside at some distance from the supporting arch, a supporting part which is connected to the first joint part. In case of an overload, at least one supporting part comes to rest on the supporting arch. The supporting arches provide protection against an overload of the armature, the armature particularly becomes more capable of withstanding forces that severely stress the two joint parts against each other, as for example in the case of loads occasioned by an accident and exerted onto the seat back of a vehicle seat.
It furthermore proved advantageous to have the toothed quadrants located on arms which extend from a main body of the second joint part and preferably have a free end. In this way, it is easy to design the toothed quadrants and the elastic means. In a preferred development, the free ends may be interconnected by elastic means. In so doing, they are elastically pretensioned relative to each other in addition to their own elasticity.
It proved advantageous to have the supporting parts arranged offset away from the main body of the second joint part relative to the plane in which the left planet wheel axle, the sluing axle and the right planet wheel axle run. Further advantages and characteristics of the invention will become apparent in the remaining claims.